Ramadi, IRAQ — Local authorities ran into a mass grave containing the relics of 40 persons in Anbar province, an official was quoted saying on Friday.

Ammar Nouri, head of the Anbar Province Martyrs Committee, said the grave was found at al-Tash region, south of the city of Ramadi.

“They were decomposed and bore signs of gunshots in the skulls,” Nouri said in statements, adding that the victims had probably been executed in 2015.

IS had notoriously executed tens of civilians and security agents in Ramadi and Fallujah after they had refused to pay allegiance to the group, Iraqi News reported.

Iraqi forces have occasionally discovered several mass graves of security members and civilians executed by IS since operations to liberate militants-held regions were launched in October. Since it took over a third of Iraq and Syria in 2014, Islamic State executed civilians and security agents for multiple reasons like collaboration with security forces and fleeing regions held by the group.

Islamic State has held the towns of Annah, Rawa and Qaim since 2014, when they occupied a third of Iraq to proclaim an “Islamic Caliphate”. So far, there has not been a wide-scale campaign to retake those regions, but occasional offensives managed to take over several surrounding villages.

The Iraqi government declared victory over ISIS in Mosul, the group’s former capital in Iraq, last month, and said it was going to proceed towards other group holdouts.

Also late July, Iraqi warplanes reportedly dropped millions of messages telling locals that liberation offensives for the province were nearing.